Luthier Tips du Jour Mailbag - CA Glue and Tie Block Bones

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In this episode, Robbie O’Brien demonstrates how to attach tie block bones on a classical guitar bridge using CA glue.

Video Transcription

[on-screen text reads: Luthier Tips du Jour Mailbag]

Mailbag question: What is the best glue for gluing bones to the tie block on a classical bridge?

Robert O'Brien: Today's Tips du Jour mailbag question comes from Francisco from the Vatican. "Dear Robert, what is the best glue for gluing the bones to the tie block on a classical bridge?"

Well, Francisco, I must confess, I've used many glues for this purpose over the years, but what truly works miracles for me is CA glue or cyanoacrylate glue. Let me show you how I do this step using this glue.

CA glue

There are a variety of CA glues and manufacturers out there. What I use is Hot Stuff from Satellite City and I get it from LMI, and it comes in a variety of flavors, thin, medium, and thick. It also comes in a user-friendly, odorless version so if the regular version irritates your eyes and nose, use the user-friendly odorless versions. Now, these glues dry pretty quickly, but if you're in a real hurry, you can use the accelerator, which dries it instantly. I would also have the super solvent around in case you decide to glue yourself to the bridge or to the bench. If you do, you would be more nervous than a lady of the night at Sunday Mass.

Tie block bones

All right, so here's my classical guitar bridge blank, here's my tie bone blocks. You want to take a look at these because sometimes they're not square, so find the squarest side and that's the side you're going to install. I'm going to take a couple of pieces of LMI binding tape and put underneath like this. This will help pull the bone into the tie block.

I'm going to be using the thick variety of the CA glue and I'm going to apply it in the channel. I'm then going to take the bone, place it in the channel, use the binding tape to pull it up in there tight [Robert presses the binding tape  down onto the tie block bone], and then I'm going to use the accelerator to quickly dry the glue [Robert sprays the accelerator on the entire length of the tie]. Once the glue's dried, pull off the tape, and I'm going to hit the excess glue here also with a little accelerator.

This next one's a little more difficult to do because you can't tape it in place. I come in with the thick viscosity glue again, place it into the channel. I then take the bone, put it in place [Robert places the bone down into the channel]. I then take a scraper, slide it into the little groove in front of the channel, and then use that to pull up everything tight, and then hit it with a little accelerator. You'll get a little accelerator behind where the scraper was and then trim the bones flush with the tie block. That's all there is to it.

Francisco, thank you for your question. When it comes to gluing in bones on the tie block on my classical guitar bridges, CA glue is my glue of choice. It would be a sin to use anything else. Happy building.

[on-screen text reads: More Luthier Tips and Online courses available at www.obrienguitars.com]

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Robbie O'Brien

Luthier and Instructor, Lutherie Academy